1. Field of the Invention
The present invention relates to a flyback transformer. More specifically, the present invention relates to a flyback transformer included in a horizontal deflection circuit for a cathode ray tube (CRT) which is utilized in a television receiver, for example.
2. Description of the Prior Art
As shown in FIG. 1, a horizontal deflection circuit includes a flyback transformer 1 which includes a primary coil PC and a plurality of secondary coils SC1 through SC4 which are magnetically coupled to the primary coil PC, and rectifying diodes D1 through D4 are connected between the respective secondary coils SC1 through SC4. A horizontal pulse generation circuit 2 is connected to the primary coil PC, which is constructed from a transistor Tr, a damper diode Dd, a resonance capacitor Cp, a direct current power source E, and so on.
FIG. 2A and FIG. 2B shows one example of a conventional flyback transformer 1, wherein the secondary coils SC1 through SC4 are divided and wound on a bobbin with flange 3 (section winding). In a flyback transformer 1 shown in FIG. 3A and FIG. 3B, the respective secondary coils SC1 through SC4 are sequentially wound on the primary coil PC in a laminated fashion (plane winding).
Since a film capacitor (1,000-6,000 pF) is utilized as the resonance capacitor Cp in the horizontal deflection circuit shown in FIG. 1, there is the problem that a large space is required and, since the resonance capacitor Cp is connected to the flyback transformer 1 as a discrete component, there is the further problem that productivity is low.
In addition, in either type of the flyback transformer as shown in FIG. 2A and FIG. 2B or FIG. 3A and FIG. 3B, since the secondary coils SC1 through SC4 are disposed on the primary coil PC, only inside portions of the secondary coils are close to the primary coil PC and an outside portion thereof is apart from the primary coil PC. Therefore, magnetic flux is leaked from the outside portion of the secondary coils, and therefore, the secondary leakage inductance becomes large. Therefore, in the conventional flyback transformer 1, voltage regulation which is a function of a vector sum of the secondary leakage inductance and a secondary resistance component is large. In addition, ringing occurs due to undesired resonance between the stray capacitance, between the primary coil, and the secondary coil and the secondary leakage inductance, and therefore, there is the further problem that a striped pattern occurs on a screen of a television receiver.